For our first post of Desert Week 2011, we’re travelling to the Grand Erg Oriental, or ‘Great Eastern Sand Sea’ of the Sahara desert in north-eastern Algeria, where we find a mysterious formation in the sand… The image was taken in 2005, and shows what appears to be a 100 metre-long (328 ft) groove gouged from the desert sand. Your first thought might be that a plane crashed here, but there’s no sign of any wreckage. However, with the constantly shifting sand it’s entirely possible that any evidence of a crash has simply been covered over, but then…